Chinese units of measurement

Chinese units of measurement (Chinese: 市制; pinyin: shìzhì; literally: "market system") are the customary and traditional units of measure used in China. In the People's Republic of China, the units were re-standardised during the late 20th century to make them approximate SI (metric) units. Many of the units were formerly based on the number 16 instead of 10. In Hong Kong, the British Imperial system was used together with Hong Kong units of measurement, which were traditional Chinese weights and measures, and now traditional Chinese units and Imperial units are used alongside the metric system, which was introduced by legislation in 1976 as the official standard system of weights and measures. Taiwanese units of measurement, which appeared under the colonial influences of the Dutch and the Japanese, for the most part may have similar names but are different from the Chinese units of measurement. Taiwan is now fully metricated.

The Chinese name for most SI units is based on that of the closest traditional unit. When it is necessary to emphasize which system is used, the words "market" (市 shì) for traditional units or "common/standard" (公 gōng) for SI units may be added in front of the name. SI is the official system of units, but traditional units are still ubiquitously used in everyday life.

Note: The names lí (厘) and fēn (分) for small units are the same for length, area, and mass; however, they refer to different kinds of measurements.

In the Zhou Dynasty, the king conferred nobles with powers of the state and the measurement units began to be inconsistent from state to state. After the Warring States period, Qin Shi Huang unified China, and later standardized measurement units. In the Han Dynasty, these measurements were still being used, and were documented systematically in the Book of Han.

Astronomical instruments show little change of the length of chi in the following centuries, since the calendar needed to be consistent. It was not until the introduction of decimal units in the Ming Dynasty that the traditional system was revised.

On 7 January 1915, the Beiyang Government promulgated a measurement law to use not only metric system as the standard but also a set of Chinese-style measurement.[1] On 16 February 1929, the Nationalist Government adopted and promulgated The Weights and Measures Act[2] to adopt the metric system as the official standard and to limit the newer Chinese units of measurement (Chinese: 市用制; pinyin: shìyòngzhì; literally: "market-use system") to private sales and trade in Article 11, effective on 1 January 1930.[3]

On 27 February 1984, the State Council of the People's Republic of China decreed the market system to remain acceptable till the end of 1990 and ordered the transition to the national legal measures by that time, but farmland measures would be exempt from this mandatory metrication until further investigation and study.[5]

On 24 August 1992, Macau published Law No. 14/92/M to order that Chinese units of measurement similar to those used in Hong Kong, Imperial units, and United States customary units would be permissible for five years since the effective date of the Law, 1 January 1993, on the condition of indicating the corresponding SI values, then for three more years thereafter, Chinese, Imperial, and US units would be permissible as secondary to the SI.[8]

Traditional units of length include the chi (尺), bu (步), and li (里). The precise length of these units, and the ratios between these units, has varied over time. 1 bu has consisted of either 5 or 6 chi, while 1 li has consisted of 300 or 360 bu.

In the case of volume, the market and metric shēng coincide, being equal to one litre as shown in the table. The Chinese standard SI prefixes (for "milli-", "centi-", etc.) may be added to this word shēng.

Units of volume can also be obtained from any standard unit of length using the prefix 立方 lìfāng ("cubic"), as in 立方米 lìfāng mǐ for a cubic metre.

As there were hundreds of unofficial measures in use, the bibliography is quite vast. Up to the 1980s or so, the book by Wu Chenglou (吳承洛), Zhongguo dulianghengshi (中國度量衡史), first printed in 1937 and republished/revised a few times since (1957, 1993), was often used as reference. It relies however mostly on literary accounts. Newer research has put more emphasis on archeological discoveries.[15] From this latter body of work, an abridged Chinese-English overview book appeared in 2005.[16] Alas, no comprehensive text appears to exist in English. A relatively recent and comprehensive bibliography, organized by period studied, has been compiled in 2012 by Cao, Theobald, Vogel, et al.;[17] for a shorter list see Wilkinson's Chinese history: a manual (2000).[15]

Hill, John E. (2009) Through the Jade Gate to Rome: A Study of the Silk Routes during the Later Han Dynasty, 1st to 2nd Centuries CE. John E. Hill. BookSurge, Charleston, South Carolina. ISBN 978-1-4392-2134-1.